The MTA has started training subway operators and staff for the long-awaited 7 line extension to 34 Street - Hudson Yards.

The $2.4 billion extension and station at 34th Street and 11th Avenue is set to open later this summer. The MTA released a video on Monday showing train dispatchers getting on-the-job training. The MTA expects to train 12 tower operators, eight dispatchers and 672 train dispatchers on the 7 line extension by the end of the month.

An official opening date is expected in the next few weeks.

“Providing this training for our subway personnel is one of the last steps toward opening the 7 Line Extension for revenue service,” MTA New York City Transit President Carmen Bianco said in a statement.  “The 7 Line Extension will open up the far west side to mass transit for the first time, and the new station and additional tail tracks for train storage will also improve service for customers using the line in Queens and Manhattan.”

Construction on the line started in December 2007 and has been delayed several times.